aphthitaliteMin.|æfˈθɪtəlaɪt| [mod.f. (1835) Gr. ἄϕθιτ-ος undecaying + λίθος stone; so called because unalterable in the air (Dana).] A native sulphate of potash found upon lava at Vesuvius; also called Vesuvian Salt, Aphthalose, Arcanite, and Glaserite.